I had issue before with python.
After upgrade default python was 3.1, I've made eselect python 1 (python 2.7)
and made python-udapte
But now when I'm trying to emerge python it gives me again python 3.1
Strange

I have both python-2.7 and python-3.1 installed, but default python should not automatically switch unless you eselect another slot.
python-updater should also be run each time you have a python update. BTW tell us if reemerging libffi (with oneshot so it won't get in world) and gobject-introspection fixes your issue.

EDIT: If it proposes you to emerge python-3.1 it should be marked as [ NS ] as in New Slot so emerging it should'nt change your default python and you should still have bot python-2.7 and python-3.1 when the emerge ends._________________Arkhelion

The presence of libffi.so.6 says that the library was upgraded, but not all programs linked to the old version have been rebuilt. A revdep-rebuild is the most likely solution at this point. Rebuilding dev-libs/libffi does not help because libffi.so.5 is part of an outdated version of the package, and rebuilding instead reinstalls libffi.so.6.

The presence of libffi.so.6 says that the library was upgraded, but not all programs linked to the old version have been rebuilt. A revdep-rebuild is the most likely solution at this point. Rebuilding dev-libs/libffi does not help because libffi.so.5 is part of an outdated version of the package, and rebuilding instead reinstalls libffi.so.6.

There's something strange going on here.

While being on arch ~amd64, 6 months later I would assume that libffi.so.6 would be standard. It is not. With the help of this topic I was able to solve my own update problems including gdk-pixbuf and chromium by a revdep-rebuild, which resulted in

However, unlike your suggestion, libffi.so.6 is not installed and libffi.so.5 remains (I even rebuilt dev-libs/libffi-3.0.10 but that didn't change a thing...). Now I'm puzzled as to why this g-ir-compiler expects and even depends on a future version of a library??

I've got into this situation, with over 500 files to update, and libfii.so.6 not available. After reading this it looks like There was a libfii.so.6 but for some reason the new version is libfii.so.5 messing all sorts of stuff up.